Synthetic oriental emerald or emerald-green sapphire



Patented Sept. 16, 193i) PATENT OFFIE ERNST e. SANDMEIER, or LOGARNO, SWITZERLAND, AssIeuon 'ro swrss JEWEL co.

a, or LoeAauo, SWITZERLAND SYNTHETIC UR-IENTAL EMERALD O15 EMERALD-GREEN SAPPHIRE No Drawing. Application filed February 28, 1928, Serial No. 257,794, and in Switzerland January 19, 1928.

The present invention relates to synthetic oriental emeralds or emerald-green sapphires'which are substantially identical in their chemical and physical properti s with,

and quite equivalent in colour and tr parency to, the natural oriental en'iera Various artificial gems have been manufactured heretofore synthetically, such. as rubies and blue and bottle-green sapph; s, but an emerald-green sapphire almost indistinguishable from the natural oriental emerald has not yet been manufactured. The apparatus and the process of manufacturing the em accordinrr to the present invention is very like that known as til- Verneuil apparatus and process and cen1- prises essentially a blow pipe producing an oxy-hydrogen flame (see Patents Nos. 988,230 and 1,00%,505, granted to A. V. L. Verneuil March 28 and Sept. 26, 1911, respectively.

The constituent materials which are subjected to said process are powdered aluminium oxide, cobalt oxide, vanadium oxide and nickel salt. These elements are mixed and caused to fall through a flame on a support offire clay where they a'e fused and form the artificial stone by successive cap-shaped layers such as has been set forth in Pat nt 1,004,505 mentioned above.

The proportions of the powdered ingredients are substantially 98,675 aluminium oxide, O,986% cobalt oxide. 0,l19% vanadium oxide and 02.95% nickel salt. ther compounos of these metals could also be 5 used owing to the fact that such compouncs, at the temperature of the flame kept up during the tormin of the stone, will be reduced to the first named compounds. But care must be taken to maintain the true pro portions by calculating the proportions according to the chemical values of the compounds employed.

The physical properties of the synthetic oriental emerald according to the pre....nt invention are, with the exception of its bcautiiul reen colour and-its transparency, the same as those stated in the case of the synthetic sapphires obtained according to the later Verneuil patent, to wit:

The synthetic stones produced by the above method and apparatus have a hardness of 9, diamond being 10, and may be distinguished on the market from the natural stones by observing the following difi'er ences in their physical characteristics Cracks or scratches are often seen in the natural stones under a high-power microscope, but they seem to be on the surface and resemble the parallel scratches made by a tile on the edge of a glass plate. They are probably due to the cutting operation. In the synthetic stone, on the other hand, the cracks, when they occur, appear as genuine rifts beneath the surface, and are generally curved, due probably to the curved layers out of which the stone is formed. T he layers comprising the natural stone are Hat and parallel, while those of the synthetic stone are curved, as above stated. The specks or cavity-like spots appearing in the natural stone are bounded by angular or or, alshaped walls, while those occurring; in the synthetic stone have curved or bubbledike walls. The above characteristics in nearly all cases must be looked for with a highpower microscope. When cut, however, the transparency and other optical properties of the natural and synthetic stones may be considered identical.

Vhat I claim as new is:

1. A composition of matter adapted to produce oriental emerald sapphires and containing aluminium, cobalt, vanadium and nickel in such proportions that when heated to a suitable temperature there will be pro duced a mass containing substantially 98.6% aluminium oxid, 0.986% cobalt oxid, 0.119% vanadium onid and 0.295% nickel OXlCl.

2. A synthetic crystalline corundum prod not having an emerald-green colour, containing 100 grammes aluminium oxid, l gramme cobalt oXid, 0.12 gramme vanadium oxid, and 0.3 nickel salt.

In testimony whereof I aifii; my signature.

ERNST G. SriNDMElER. 

